The specific epithet straminea means straw colored (Fernald 1970). It is unclear why this epithet was applied to this species.
There are five known populations and possibly up to 50 historical locations; however, there has been much taxonomic confusion with this plant and all voucher specimens should be verified. Of the known populations, only one has more than a hundred plants and three are of questionable viability. As a species of freshwater marshes, this is threatened by Phragmites, purple loosestrife, and other invasive species.
Only a handful of populations have been seen in recent years. Most of these are quite small although at least one population has over 500 plants. It is unknown if the small populations indicate a decline. Therefore, short term trends are unclear.
There are at least 50 reported or vouchered populations that have not been seen in recent years. Many of these populations may have been misidentified in the past and may not be populations of C. straminea. Two populations are believed extirpated due to habitat loss. Vouchers for these populations should also be confirmed to determine if these populations were truly C. straminea populations. Overall, long term trends are unclear.
At one population there are a few potential threats including nutrient enrichment from agricultural run off, trampling by people fishing, flooding of the habitat by beaver, and development of the wetland edges.
Habitat at one populations needs to be protected from flooding by beaver and trampling by people. Additionally, this site needs to be secured from development. Before these management practices are implemented, voucher specimens need to be verified.
All voucher specimens should be verified. After verification of specimens, historical populations should be surveyed to determine if they are still extant.
In New York, Carex straminea is known from swamp margins and marshes. One population is in a wet field at sea level and the water is probably brackish. Other sites are from drier situations. Specimens documenting these habitats especially the brackish and upland habitats need to be verified as they may be misidentified (New York Natural Heritage Program 2006). Freshwater marshes, shores, and swales, wet woods, in sandy or peaty, acidic soils (Mastrogiuseppe et al. 2002). Non-saline swamps and wet meadows (Gleason & Cronquist 1991). Marshes and swamp borders (Voss 1972). Fresh swamps and swales (Fernald 1970). In acid soils in swampy woodlands (Mackenzie 1931-1935).
There are reports and specimens labeled C. straminea from central New York as well as eastern New York south to New York City and Long Island. Many of these reports and records are probably misidentifications due to the confusing taxonomic history of C. straminea. It does appear that correctly identified populations of C. straminea occur on Long Island, in southeastern New York, and at least one population in western New York. Still, the specimens documenting these populations should be verified.
Carex straminea occurs in widely separated populations throughout it range. It is known from Rhode Island, Connecticut, and New York south to North Carolina west to Missouri, Illinois, and Wisconsin (Mastrogiuseppe et al. 2002). Mackenzie (1931-1935) has a much larger range for C. straminea. This is because Mackenzie misapplied the name C. straminea to C. albolutescens and instead used the name C. richii for C. straminea (Mackenzie 1931-1935, Fernald 1970).
Straw sedge is a tufted grass-like perennial. Leaves are 1.5-3.0 mm wide. As with other members of section Ovales some stems have flower/fruit clusters (spikes) at the apex of the stems (reproductive stems) and some stems lack these structures (vegetative stems). The vegetative stems are conspicuous and have numerous leaves on them. Reproductive stems are 35-100 cm tall and have 3-4 leaves on the lower part of the stems. At the apex of these stems are 3-7 stalkless somewhat round clusters of flowers/fruits (spikes). The spikes are widely spaced and the upper flowers in these spikes are female and the lower male. The female flowers develop into fruits (perigynia) which are round and taper to a beak at their apices. They are 4.0-5.6 mm long and 1.8-2.8 mm wide (Mackenzie 1931-1935, Mastrogiuseppe et al. 2002).
Carex straminea is densely cespitose and short rhizomatous. Leaf sheath adaxial surfaces (fronts) are veined and have at most a narrow hyaline region at the summit. The blades are 3-4 mm wide. Reproductive culms are 35-100 cm long and extend beyond the leaves. The inflorescences nod and are composed of 3-7 separated globose gynecandrous spikes. The bases of the pistillate region, of the lateral spikes, abruptly taper to the staminate portion which is 2-6 mm long. Pistillate scales are reddish brown, acuminate or awned at their apices, and mostly are shorter than the perigynia they subtend. Perigynia are spreading, 4.0-5.6 mm long, 1.8-2.8 mm wide, have a somewhat orbiculate body, and abruptly taper to a beak (Mastrogiuseppe et al. 2002).
Just immature or mature perigynia are essential for confident identification of C. straminea. The whole plant can be useful in identification and should be collected.
Carex argyrantha and C. foenea also have nodding inflorescences. These two species have pistillate scales which consistently are longer that the tips of the perigynia.
Carex tenera which also has nodding inflorescences has perigynia ovate to broadly ovate and narrower [1.4-1.9(-2.0) mm wide]. In comparison, C. straminea has perigynia somewhat orbiculate and wider [1.8-2.8 mm wide].
Carex hormathodes is somewhat similar. It has spikes ellipsoid, the pistillate portions gradually tapering at their bases, and the staminate portions of the spikes equal to or less than 2 mm long. In comparison, C. straminea has spikes globose, the bases of the pistillate portions abruptly tapering at their bases, and the staminate portions of the spikes 2-6 mm long. In addition, C. hormathodes has shorter beaks, perigynia bodies lance-ovate to barely obovate, and grows in maritime areas often getting some salt spray. C. straminea has longer beaks, perigynia bodes somewhat orbiculate, and grows in freshwater wetlands.
Carex straminea starts to produce immature perigynia in early July. These mature and persist into mid-August. Toward the end of this season the fruits are starting to shed easily. Therefore, the best time to survey for this species is from July through early August.
The time of year you would expect to find Straw Sedge fruiting in New York.
Carex straminea Willd. ex Schkuhr
Carex straminea is in section Ovales. The name C. straminea has been incorrectly applied at times to C. tenera (Mastrogiuseppe et al. 2002). Some specimens labeled as C. straminea in New York have been determined to be other species including C. albolutescens. This maybe in part because C. albolutescens is considered a synonym of C. straminea by Mackenzie (1931-1935) and the name C. straminea was misapplied by Mackenzie to C. albolutescens. In addition, many species used to be considered varieties of C. straminea including C. tenera sensu lato (C. straminea var. echinodes), C. normalis (C. straminea var. mirabilis), C. cumulata (C. straminea var. cumulata), C. brevior (C. straminea var. brevior), C. foenea (C. straminea var. foenea), C. festucacea (C. straminea var. festucacea), and more (Mackenzie 1931-1935). Therefore, all specimens of C. straminea should be examined critically to determine their true identification.
Mastrogiuseppe, J., P.E. Rothrock, A.C. Dibble, and A.A. Reznicek. 2002. Carex Linnaeus sect. Ovales Kunth. Pages 332-378 in Flora of North America Editorial Committee (editors), Flora of North America, north of Mexico, Volume 23, Magnoliophyta: Commelinidae (in part): Cyperaceae. Oxford University Press, New York, New York, USA. 608pp + xxiv.
Fernald, M.L. 1950. Gray's manual of botany. 8th edition. D. Van Nostrand, New York. 1632 pp.
Gleason, Henry A. and A. Cronquist. 1991. Manual of Vascular Plants of Northeastern United States and Adjacent Canada. The New York Botanical Garden, Bronx, New York. 910 pp.
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Mackenzie, K.K. 1931-1935. Cariceae. North American Flora 18: 1-478.
Mitchell, Richard S. and Gordon C. Tucker. 1997. Revised Checklist of New York State Plants. Contributions to a Flora of New York State. Checklist IV. Bulletin No. 490. New York State Museum. Albany, NY. 400 pp.
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Reschke, Carol. 1990. Ecological communities of New York State. New York Natural Heritage Program, New York State Department of Environmental Conservation. Latham, NY. 96 pp. plus xi.
Voss, E.G. 1972. Michigan Flora, Part I. Gymnosperms and Monocots. Cranbrook Institute of Science Bulletin 55 and the University of Michigan Herbarium. Ann Arbor. 488 pp.
Weldy, T. and D. Werier. 2010. New York flora atlas. [S.M. Landry, K.N. Campbell, and L.D. Mabe (original application development), Florida Center for Community Design and Research http://www.fccdr.usf.edu/. University of South Florida http://www.usf.edu/]. New York Flora Association http://newyork.plantatlas.usf.edu/, Albany, New York
Information for this guide was last updated on: May 31, 2006
Please cite this page as:
New York Natural Heritage Program. 2020. Online Conservation Guide for Carex straminea. Available from: https://guides.nynhp.org/straw-sedge/. Accessed July 9, 2020.